JPS58133619A - Manufacture for thin film magnetic head - Google Patents

Abstract

PURPOSE:To reduce the residual internal stress of a magnetic substance layer and to manufacture a head with high performance, by forming a magnetic substance layer at a temperature at which the residual stress is a true stress mainly and annealing the layer at a temperature lower than the recrystallizing temperature of the magnetic substance layer. CONSTITUTION:As a base 1, 0.2mm. thick silicon wafer is used and a permalloy film, 2mum thick is formed with the planer magnetron type sputtering device under 5X10Torr. Ar gas pressure as the magnetic substance layers 2, 6. The forming of the layers 2, 5 is done by keeping the temperature of the base 1 to 100 deg.C. Other conditions are the same as conventional methods. As to the samples obtained as above, annealing is done for two hours under 5X10Torr. vacuum at 250 deg.C, 300 deg.C, 350 deg.C and 500 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a thin film magnetic head having a structure in which a conductor layer is sandwiched between magnetic layers.

The general structure of a thin film magnetic head and its conventional manufacturing process will be explained with reference to the drawings.

First, a magnetic layer 2 made of a ferromagnetic material such as permalloy is formed on a substrate 1 made of silicon or ceramic by a method such as vapor deposition, electrodeposition, or sputtering. This magnetic layer B is formed into a predetermined shape by wet or dry etching, and then vapor deposited thereon.

Electrical insulator I#48 of organic resin or the like is formed by electrodeposition, sputtering, *cloth, printing, or other methods. An electrically conductive layer 4 is formed thereon, which is etched into a predetermined shape, and then an electrically insulating layer 6 is formed thereon. On this electrically insulating layer, a magnetic layer 6 is formed using the same material as the magnetic layer 2 by the same method, and is etched into a desired shape. In this way, a magnetic circuit is formed between the magnetic layers 8.6.

By the way, when using a permalloy film obtained by vapor deposition or sputtering as a material for a thin film magnetic head, it is common to apply a magnetic field with a coil or magnet to induce uniaxial anisotropy on the film surface. It is. This is the same in the case of a thin film magnetic head, and the magnetic material layer 2.
6 is placed in a magnetic field. By doing so, the switching performance of the thin film magnetic head can be improved.

Additionally, permalloy and the like have stress sensitivity, a phenomenon in which the magnetic properties are influenced by the relationship between magnetostriction and stress. In order to prevent the characteristics of the thin film magnetic head from deteriorating due to this stress sensitivity, it is desirable to reduce the internal stress remaining in the magnetic layers S and 6 as much as possible.

Here, there are two directions for selecting the composition of the magnetic layer 2.6. One is to select a composition with a small magnetic φ in order to reduce stress sensitivity. The other is negative to actively utilize stress sensitivity.

A positive magnetostrictive composition is selected. Although the magnitude of the stress remaining in the magnetic layer 2゜6 varies depending on the method used to form it, the former aims to prevent the characteristics from being influenced by the magnitude of this stress. The latter is what I'm trying to use.

However, whichever composition is selected, it is necessary to reduce the internal stress remaining in the magnetic layers S and 6 as much as possible.

That is, even if a composition with zero magnetostriction is selected, the actually obtained magnetic layer 3.6 usually has a certain degree of distribution on the positive and negative magnetostrictive sides. Next, there is a case where internal stress is actively utilized, but in this case, the formation conditions of the magnetic layer 3.6 become an issue. That is, the magnetic layer S
, 6 includes the intrinsic stress of the layer itself and the thermal stress caused by the difference in coefficient of thermal expansion between the layer and the substrate during electrodeposition, sputtering, or vapor deposition. Generally, when formed at a low temperature, intrinsic stress remains as residual stress, and when formed at a high temperature, thermal stress remains as residual stress. Even if such internal stress is isotropic at the time of forming the magnetic layer, when it is patterned into the desired shape, if the shape is other than circular, it will become anisotropic stress and will not meet the desired shape. There is a risk that the direction of the uniaxial anisotropy may be shifted. For this reason, the magnetic layer 8.6
Regardless of the composition selected, it is important to reduce residual internal stress.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a thin film magnetic head with excellent performance by significantly reducing the internal stress remaining in the magnetic layer.

The main feature of the present invention, however, is that after forming the magnetic layer of the thin-film magnetic head, annealing is performed to reduce the internal stress remaining therein. This annealing may be performed each time an individual magnetic layer is formed, or may be performed on two magnetic layers at once in the final stage. The effect of reducing internal stress due to annealing is remarkable in the buttocks compared to the above-mentioned intrinsic stress. Therefore, the effects of the present invention are most significant when each magnetic layer is formed at a relatively low temperature where only intrinsic stress remains.

Examples of the present invention will be described below.

! *Example of treatment The structure of the single-film magnetic head is as shown in the drawing.

Using 0.2 μm of silicon urethane as the substrate,
As the magnetic layer 2.6, a permalloy film with a thickness of 2 μm was sputtered using a planar magnetron type sputtering device using a 5xlOTor.
Formed under roA1 gas pressure. However, magnetic layer 3.6
The formation of is carried out by keeping the temperature of the substrate l at 100°C.

Other than this, it is the same as before.

For the sample obtained as above, 5X10 TOrr
250℃, 800℃, 850℃, 500℃ in vacuum
Annealed at each temperature for 2 hours. Regarding these samples after annealing and samples that were not annealed,
The internal stress of the magnetic layer 6 was measured by the disk method. The measurement results are shown in Table 1.

Example 2 The substrate temperature at the time of forming the magnetic column layer 2.6 was 150° C., and nine samples were made under the same conditions as in Example 1 except for the following conditions: 250° C.,
Annealing was performed at 800°C, 850°C, and 500°C in an oxygen-free atmosphere. The internal stress of the magnetic layer 6 was measured using the disk method for the samples after the annealing treatment and the samples that were not annealed. The measurement results are shown in Table 1.

Example 8 Nine samples were obtained using the same method and conditions as in Example 1, except that the substrate temperature was 200°C and the magnetic layer 2.6 was formed at 250°C, 800U, 85 in an oxygen-free atmosphere.
Annealing was performed at 0°C and 500'C4C. The internal stress of the magnetic layer 6 was measured using the disk method for the annealed sample and the non-annealed sample. The measurement results are shown in Table 1.

Example 4 A sample obtained using the same opening method and conditions as in the example was subjected to the same annealing treatment as in the example, except that the substrate temperature during formation of the magnetic material NI2.6 was 850°C. The internal stress of the magnetic layer 6 was measured using the disk method for these samples and a sample that was not annealed. The measurement results are shown in Table 1.

Table 1 As is clear from Table 1, the lower the substrate temperature at the time of forming one magnetic layer, the greater the internal stress remaining in it, but the reduction effect by annealing also increases, and the annealing temperature 8
After annealing at 50°C, the internal stress decreases to an extremely small value of almost the same level. The effect of reducing internal stress tends to increase as the annealing temperature increases, but at an annealing temperature of 500°C, the internal stress increases on the contrary. This is because if the annealing temperature is too high, recrystallization of the magnetic layer will occur.

Therefore, for the purpose of the present invention, it is necessary to set the annealing temperature lower than the recrystallization temperature of the magnetic layer.

As described above, according to the present invention, the internal stress remaining in the magnetic layer can be significantly reduced, and a high-performance thin-film magnetic head can be obtained, which is extremely effective.

[Brief explanation of drawings]

The figure is a sectional view showing an example of a thin film magnetic head. 1...Substrate, 2.6...Magnetic material layer, 8.5...Electric insulation layer, 4...Electric conductor layer. 4 5 c. 1 2 5

Claims (1)

[Claims] L A method for manufacturing a thin film magnetic head having a configuration in which a conductor layer is sandwiched between magnetic layers, which includes an annealing step for reducing residual stress in the magnetic layer after forming the magnetic layer. □Method for manufacturing thin film magnetic heads, including mold. 2. The method of manufacturing a thin film magnetic head according to claim 1, wherein the annealing step is performed at an annealing temperature lower than the recrystallization temperature of the magnetic layer. 3. The above-mentioned magnetic layer is formed at a temperature at which the stress remaining after its formation becomes mainly intrinsic stress.
#Required Range: A method for manufacturing a thin film magnetic head according to item 1.